FCGRT encodes the alpha-chain of the neonatal Fc receptor (FcRn), a critical regulator of immunoglobulin G (IgG) and albumin trafficking across epithelial and endothelial barriers 1. The primary function of FcRn involves IgG recycling and transcytosis, enabling prolonged IgG half-life and systemic distribution 1. Additionally, FCGRT acts as an uncoating receptor for echoviruses, facilitating viral cellular entry through an alternative infection mechanism. FCGRT expression is tightly regulated through multiple epigenetic and transcriptional mechanisms. DNA methylation in the -1058 to -587 bp regulatory region affects FCGRT transcription via methylation-sensitive transcription factors Zbtb7a and Sp1 1. MicroRNA-3181 post-transcriptionally suppresses FCGRT mRNA and FcRn protein expression by approximately 40-70% 2. Promoter analysis identified critical Sp1 sites and AP-1 motifs essential for tissue-specific FCGRT regulation 3. Clinically, FCGRT polymorphisms influence IgG serum levels and therapeutic antibody pharmacokinetics 4. FCGRT-humanized mouse models demonstrate that genetic variation affects in vivo antibody-mediated viral protection, independent of in vitro neutralizing titers 5. Additionally, FCGRT variants associate with fructosamine levels, suggesting metabolic regulation 6, while elevated FCGRT expression in keloid macrophages correlates with aberrant tissue fibrosis 7.